Coincidence, Identity and Sortals: On Mackie’s “Coincidence and Identity”
Ezequiel Zerbudis.
Penelope Mackie argues, in “Coincidence and Identity”, against a particular solution to the puzzles originated in cases of alleged coincidence of material objects, the one she calls “Intermediate Monism”, and then tries to defend a Pluralist way of construing such cases. The kind of position that she criticizes consists in asserting that, while in cases of so called permanent coincidence, the objects involved are considered to be identical, this is not so in the cases of temporary (same or different-origin) coincidence. Part of what seems to Mackie to be unsatisfactory about this proposal (and which, I could agree, is unsatisfactory) is that, contrary to what is the case with other proposed solutions, it treats so differently these cases in which, so it seems, almost everything that is relevant is similar. Mackie’s preferred account, Pluralism, does not have this drawback, as it presents a uniform solution for all cases of coincidence (both permanent and temporary): according to this position, in all cases of coincidence what happens is that there are different objects that occupy the same space during the same period of time.
In this brief commentary, I would like to raise some doubts about two particular aspects of the argumentation she displays in her paper: on the one hand, I don’t think that the way in which she tries to obtain support for her Irrelevance of the Future principle (IOF) is adequate; on the other hand, I don’t agree with the way in which she construes the notion of a sortal, as it appears in her discussion of the different intrinsic similarity principles at the end of her paper. I deal with these two issues in turn.
The first issue that I would like to discuss concerns, then, what can be seen as the first part of Mackie’s paper (sections 1-6), in which she argues against the Intermediate
Monist’s treatment of coincidence cases.
She considers three different arguments that could be advanced against that position and, after analyzing and rejecting the first two of them because, in her opinion, they do not succeed in refuting the Intermediate Monist’s position, she goes on to present a new argument of her own, which she considers that does achieve its goal. The discarded arguments are those based in an appeal to Leibniz’s Law and modal predication, on the one hand, and, on the other hand, those based on the alleged incompatibility of the
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persistence conditions associated with some relevant sortals (arriving at the conclusion that these are incompatible only when understood with de re modal implications). Her own argument is based on the, as she says, “deeply counterintuitive” character of the difference that the Intermediate Monist is supposed to find between cases of permanent coincidence and cases of same-origin temporary coincidence. In fact, while the
Intermediate Monist is committed to saying that a statue and a lump of clay are identical when they coincide at all times of their existence, he is also committed to saying that they are distinct when they coincide through their whole existence but for some brief period of time at the end of their careers.
I will not be concerned here with the details of Mackie’s arguments, but only with the premise that ultimately grounds her conclusion, a premise which is as follows (I quote):
(IOF) The irrelevance of the future : If this piece of clay is a statue at time t , its being a statue at t is independent of events that occur later than t .
Stated this way, this thesis seems unobjectionable. It is clear that in most cases we can tell, after a brief inspection, and eventually after hearing about that object’s history, whether a certain object is or is not, at that time, a statue. But this can be used against the Intermediate Monist (which in most cases is also a perdurantist) only if “is a statue” is understood as stating the same as “is identical with a certain statue”. But there are two problems with this equivalence: on the one hand, the thesis becomes much less plausible and intuitively acceptable, because it is not clear that that much is what we suppose to be judging when, on examining an object in front of us, we say “That’s a statue”; on the other hand, assuming that much seems to me to beg the question against the perdurantist.
Both of these suspicions could be motivated, it seems to me, if we distinguish two different ways in which a predicate such as ‘is a statue’ could be understood:
(1) On the one hand, I think that there is a reading that could be called the “strictly sortal” reading, which is, as far as I understand her correctly, Mackie’s intended interpretation. According to this construal of the predicate, the common noun that appears in it (‘statue’ in our example) functions as a sortal in the sense of stating what the thing in question is (and, in consequence, what its persistence conditions are). And it is only on this reading, I think, that ‘ x is a statue’ could be understood as implying, as
Mackie intends, ‘ x is identical with a statue’ (if it is not even synonymous to that
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predicate, in case the ‘is’ of ‘is a statue’ should be understood as Wiggins’ ‘is’ of identity; but I am not sure what to say about this).
(2) On the other hand, I think there is also a possible reading of ‘is a statue’ that we could call “predicative”. On this construal, this predicate would be used to say of a certain object that it has those properties that statues typically have, while remaining non-committal as to whether that object is or not, in fact, identical to an object of that kind (in the sense in which the noun ‘statue’ says what that object is).
As could be inferred from what I have said before, I think that IOF could only be intuitively plausible if the predicate ‘is a statue’ that appears there is understood with this second meaning. But, in that case, that premise could not justify the conclusion
Mackie intends to draw from it, namely, that the future is irrelevant to our judgments of identity (and that therefore cases of same-origin temporary coincidence should be treated as similar to cases of permanent coincidence). And I also think that, if this were not so, that is, if we understood ‘is a statue’ in IOF as if it had the first meaning, that is, if we supposed that one could assert at some time that a certain object is identical with an object of some sort with independence of its future career, then we would be begging the question against the Intermediate Monist.
But, it could be asked, is it true that there is such a predicative reading of ‘is a statue’?
Well, I think it is. I have only found the notion of a predicative use of a sortal, more or less in the sense in which I use it here, in Burke’s writings on the topic (see, for instance, his “Preserving the Principle of One Object to a Place …”, p. 595) but, it could be said, his treatment of sortals is far too unorthodox, so that we had better not rely on such an authority. Anyway, pluralists have long been acquainted with what I think is a special case of such uses of sortals: those in which they form predicates together with
Wiggins’ ‘is’ of constitution. Let’s take a case of different -origin partial coincidence, the case in which we had our lump of clay for some time on our bench, and one day we decided to make a statue out of it. It would be perfectly natural to say that our lump is now a statue. But what we probably mean, and Wiggins would be the first to point it out, is not that both are identical, but that our lump has acquired some properties that would allow us to describe it as a statue or, in Wiggins’ jargon, that the lump constitutes the statue. In a sense, to formulate my objection to Mackie’s way of arguing for IOF, I don’t even need to establish that there are such things as predicative uses of sortals
(which could probably be characterized as uses with the ‘is’ “of coincidence”), it would be enough if I could show that there are non-identity-involving uses of sortal predicates
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such as ‘is a statue’ or ‘is a lump of clay’, and that these are arguably those used in the context of IOF – and for this, it seems that what has been said is enough.
Moreover, I suspect that the situation for Mackie is even more problematic. Given that she has endurantist and pluralist preferences, which she tries to defend in the last part of her paper, it seems that she cannot but accept that the predication ‘this piece of clay is a statue’, as it appears in IOF, involves a use of the ‘is’ of constitution, and therefore that it cannot imply the identity between the piece of clay and the statue. And, indeed, it seems to me that she cannot, in general, endorse the implication, that she explicitly says she will suppose as always valid in the context of the paper, from ‘ x is a statue’ to ‘ x is identical with some statue’. This is so because, if she accepts that the lump is a statue, which she seems to do in IOF, she would be force to suppose that the lump is identical with the statue, which is exactly what she wanted to avoid by adopting a pluralist position. So she would seem, if what I said is correct, to have committed herself to some incompatible theses (but, of course, what is most probable is that I misunderstood much of what she says).
I now turn to the second issue I announced at the outset, which concerns the way in which she understands the notion of a sortal. In the second part of her paper (section 7), she tries to defend the endurantist and pluralist position against some objections that had been presented against it, and devotes most of her attention to the arguments, based on intrinsic similarity principles, that intend to show, against the pluralist, that constitution is identity. In particular, she considers Harold Noonan’s Constitution is Identity (CII) principle and Mark Johnston’s (8) (I quote):
(CII) Purely material entities of identical constitution at all times cannot be distinct merely in virtue of differences in modal, dispositional or counterfactual properties.
(8) If y is a paradigm statue, and x is intrinsically like y , then x is a statue.
But she rejects the force of the first principle against the pluralist position on the basis that the difference between constituent and constituted (or between any other kind of pairs of coincident objects) could instead be simply based in a difference in their sortal properties. And rejects the force of the second principle to the same effect on the basis that these sortal properties which would ground the difference of the coinciding objects
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could be, as far as we know, themselves intrinsic (so that the lump of clay would not be, after all, intrinsically like the statue).
But, even if we accept the existence of sortal properties (something I would doubt, no matter how much the applicability of sortal concepts, and the truth of predications involving them, does depend on the properties the objects have) there is something odd in supposing that such differences could ground the difference between two coinciding objects. Even setting aside Mackie’s more ambitious claim (concerning Johnston’s principle) to the effect that sortal properties could probably be intrinsic, this position seems untenable. In particular, if we accept, as seems reasonable to do, a standard conception of properties such as Armstrong’s realist conception, according to which properties are defined by causal roles, and no matter how complex we considered a sortal property to be (and some of them, such as that of being a statue, are probably very complex, having to take into account human attitudes and reactions to certain objects, the process of creation of the piece, and so on), it seems clear that if two objects, such as the lump and statue in our original example, are, in accordance to the pluralist’s principles, completely coincident through their whole history, and such that they are constituted by the same basic constituents, it seems clear, I submit, that nothing in them could provide a basis for their having different and incompatible properties, so as to ground the existence of different but coinciding real, sortal properties. This would be so because, being constituted by the same basic ingredients, both their basic properties, and any other properties which we could suppose to supervene upon them, would be the same for both “coinciding” objects. And if there is no ground for the existence of differing sortal properties, Mackie’s particular way of getting rid of Noonan’s and
Johnston’s principles is unwarranted.
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